There is only one file type that uses the .LRV extension:
Low Resolution Video File
Low Resolution Video file created in the MPEG-4 video format; produced by a number of GoPro cameras including the GoPro HERO2 and HERO3, with proper software updates required on the older cameras; created in parallel with a high definition (HD) file of the video.
LRV files are used during the editing process to reduce the amount of computing power required to edit a video compared to using the HD file. After a video is edited the LRV file can be replaced with the HD file before rendering the final video.
These files are also used for previewing with GoPro mobile applications, for playback via Wi-Fi, or as the streaming buffer when a smartphone is used as a control device.
LRV video is recorded in 240p at 29.97 frames per second regardless of the camera's settings.
To play an LRV file, simply rename the file to .MP4 and open it with any application that can open .MPEG4 video files.
Updated: September 25, 2013